Designation: A 416/A416M &#; 99
Standard Specification for
Steel Strand, Uncoated Seven-Wire for Prestressed
Concrete
1
HUAYONGXIN supply professional and honest service.
This standard is issued under the fixed designation A 416/A416M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope
1 This specification covers two types and two grades of
seven-wire, uncoated steel strand for use in pretensioned and
post-tensioned prestressed concrete construction. The two
types of strand are low-relaxation and stress-relieved (normal-
relaxation). Low-relaxation strand shall be regarded as the
standard type. Stress-relieved (normal-relaxation) strand will
not be furnished unless specifically ordered, or by arrangement
between purchaser and supplier. Grade [250] and Grade
[270] have minimum ultimate strengths of MPa
[250 ksi] and MPa [270 ksi], respectively, based on the
nominal area of the strand.
1 The values stated in either inch-pound units or SI units
are to be regarded as standard. Within the text, the inch-pound
units are shown in brackets. The values stated in each system
are not exact equivalents; therefore, each system must be used
independently of the other. Combining values from the two
systems may result in nonconformance with the specification.
1 The supplementary requirements in S1 shall be specified
for 15-mm (0-in.) diameter uncoated seven-wire steel
strand if needed for applications in prestressed ground anchors.
2. Referenced Documents
2 ASTM Standards:
A 370 Test Methods and Definitions for Mechanical Testing
of Steel Products 2
A 981 Test Method for Evaluating Bond Strength for 15.
mm (0 in.) Diameter Prestressing Steel Strand, Grade
270, Uncoated, Used in Prestressed Ground Anchors 3
E 328 Methods for Stress-Relaxation Tests for Materials
and Structures 4
2 U. Military Standards:
MIL-STD-129 Marking for Shipment and Storage 5
MIL-STD-163 Steel Mill Products Preparation for Ship-
ment and Storage 5
2 U. Federal Standard:
Fed. Std. No. 123 Marking for Shipments (Civil Agencies) 5
3. Terminology
3 Definitions of Terms Specific to This Standard:
3.1 strand , n &#;a group of wires having a center wire
enclosed tightly by six helically placed outer wires with
uniform pitch of not less than 12 and not more than 16 times
the nominal diameter of the strand.
3 Discussion &#;The direction of lay may be either right-
or left-hand, however, strands of different lays should not be
spliced together.
4. Ordering Information
4 Orders for seven-wire low-relaxation or stress-relieved
(normal-relaxation) strand under this specification should in-
clude the following information:
4.1 Quantity (meters [feet]),
4.1 Diameter of strand,
4.1 Grade of strand,
4.1 Type of strand,
4.1 Packaging,
4.1 ASTM designation and year of issue, and
4.1 Special requirements, if any.
NOTE1&#;A typical ordering description is as follows: 25 600 m [84 000
ft], 13 mm [0 in.], Grade [270] low-relaxation strand, in -m
[12 000-ft] reelless packs to ASTM A 416/A 416M&#; _________.
5. Materials and Manufacture
5 Base Metal &#;The base metal shall be carbon steel of
such quality that when drawn to wire, fabricated into strand,
and then thermally treated, shall have the properties and
characteristics prescribed in this specification.
5 Wire &#;The wire from which the strand is to be fabri-
cated shall be round and have a dry-drawn finish.
NOTE2&#;This product is a composite of seven wires and is produced to
mechanical properties only. The chemistry of all wires or any individual
wire is not pertinent to this application, and heat identity is not necessarily
maintained. It is possible that wire from more than one heat may be used
in the manufacture of a reel or pack. Traceability is based on pack identity
1 This specification is under the jurisdiction of ASTM Committee A-1 on Steel,
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
A01 on Steel Reinforcement.
Current edition approved Sept. 10, . Published December . Originally
published as A 416 &#; 57 T. Last previous edition A 416 &#; 98e 1.
2 Annual Book of ASTM Standards , Vol 01.
3 Annual Book of ASTM Standards , Vol 01.
4 Annual Book of ASTM Standards , Vol 03.
5 Available from Standardization Documents Order Desk, Bldg. 4, Section D,
700 Robbins Ave., Philadelphia, PA -.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA -, United States.
as maintained and reported by the manufacturer.
5 Treatment &#;After stranding, low-relaxation strand shall
be subjected to a continuous thermal-mechanical treatment to
produce the prescribed mechanical properties. For stress-
relieved (normal-relaxation) strand, only thermal treatment is
necessary. Temper colors which result from the stress-relieving
operation are considered normal for the finished appearance of
this strand.
6. Mechanical Properties
6 Methods of testing for mechanical properties are de-
scribed in Annex A7 of Test Methods and Definitions A 370.
Low-relaxation strand shall also be tested as prescribed in
Methods E 328.
6 Breaking Strength &#;The breaking strength of the fin-
ished strand shall conform to the requirements prescribed in
Table 1.
6 Yield Strength &#;Yield strength in kN [pounds] is mea-
sured at 1 % extension under load. The minimum yield strength
shall be 90 % for low-relaxation strand and 85 % for stress-
relieved (normal-relaxation) strand of the breaking strength
listed in Table 1. Initial loads for the test and minimum yield
strengths are listed in Table 2.
6.3 The extension under load shall be measured by an
extensometer calibrated with the smallest division not larger
than 0 mm/mm [0 in./in.] of gage length.
6 Elongation &#;The total elongation under load shall not
be less than 3 % using a gage length of not less than 600 mm
[24 in.]. In practice the total elongation value may be deter-
mined by adding to the 1 % yield extension the percent
extension or movement between the jaws gripping the strand
after yield determination. The percent is calculated on the new
base length of jaw-to-jaw distance.
6 Relaxation Properties &#;Low-relaxation strand shall
have relaxation losses of not more than 2 % when initially
loaded to 70 % of specified minimum breaking strength or not
more than 3 % when loaded to 80 % of specified minimum
breaking strength of the strand after h tested under the
conditions listed in 6.5 through 6.5.
6.5 If required, relaxation evidence shall be provided from
the manufacturer&#;s records of tests on similarly dimensioned
strand of the same grade.
6.5 The temperature of the test piece shall be maintained
at 20 6 2°C [68 6 3°F].
6.5 The test piece shall not be subjected to loading prior to
the relaxation test.
6.5 The initial load shall be applied uniformly over a
period of not less than 3 min and not more than 5 min, and the
gage length shall be maintained constant; load relaxation
readings shall commence 1 min after application of the total
load.
6.5 Over-stressing of the test sample during the loading
operation shall not be permitted.
6.5 The duration of the test shall be h or a shorter
period of at least 200 h, provided it can be shown by records
that an extrapolation of the shorter period test results to
h will provide similar relaxation values as the full h test.
6.5 The test gage length shall be at least 60 times the
nominal diameter. If this gage length exceeds the capacity of
the extensometer or testing machine, then it is permitted to
substitute a gage length of 40 times the nomimal strand
diameter.
7. Dimensions and Permissible Variations
7 The size of the finished strand shall be expressed as the
nominal diameter of the strand in millimetres [inches].
7 The diameter of the center wire of any strand shall be
larger than the diameter of any outer wire in accordance with
Table 3.
7 Permissible Variations in Diameter :
7.3 All Grade [250] strand shall conform to a size
tolerance of 6 0 mm [ 6 0 in.] from the nominal diam-
eter measured across the crowns of the wires.
7.3 All Grade [270] strand shall conform to a size
tolerance of +0, &#; 0 mm [+0, &#;0 in.] from the
nominal diameter measured across the crowns of the wire.
7.3 Variation in cross-sectional area and in unit stress
resulting therefrom shall not be cause for rejection provided
that the diameter differences of the individual wires and the
diameters of the strand are within the tolerances specified.
7 Specially dimensioned low relaxation and stress-
relieved [normal-relaxation] strands with nominal diameters up
to 19 mm [0 in.] may be employed, providing that the
breaking strength is defined, and the yield strength, as defined
in 6, is not less than 90 % and 85 % of the specified minimum
breaking strength for low-relaxation and stress-relieved (nor-
mal relaxation) strands, respectively. All other requirements
shall apply.
TABLE 1 Breaking Strength Requirements
Strand Designation No. Diameter of Strand, mm
[in.]
Minimum Breaking
Strength of Strand, kN [lbf]
Featured content:Guide to Quality Hoses for All Uses
Contact us to discuss your requirements of astm a416/a416m. Our experienced sales team can help you identify the options that best suit your needs.
Steel Area of Strand,
mm 2 [in. 2 ]
Weight of Strand kg/
m [lb/ ft]
Grade [250]
6 6 [0] 40 [9 000] 23 [0] 182 [122]
8 7 [0] 64 [14 500] 37 [0] 294 [197]
9 9 [0] 89 [20 000] 51 [0] 405 [272]
11 11 [0] 120 [27 000] 69 [0] 548 [367]
13 12 [0] 160 [36 000] 92 [0] 730 [490]
15 15 [0] 240 [54 000] 139 [0] [737]
Grade [270]
9 9 [0] 102 [23 000] 54 [0] 432 [290]
11 11 [0] 137 [31 000] 74 [0] 582 [390]
13 12 [0] 183 [41 300] 98 [0] 775 [520]
15 15 [0] 260 [58 600] 140 [0] [740]
be so conducted as not to interfere unnecessarily with the
operation of the works.
NOTE4&#;The purchaser should state, at the time of order, whether
outside inspection is required or waived.
12. Rejection
12 Failure of any test specimen to comply with the
requirements of the specification shall constitute grounds for
rejection of the lot represented by the specimen.
12 The lot may be resubmitted for inspection by testing a
sample from each reel or pack and sorting out non-conforming
material.
12 In case there is a reasonable doubt in the initial testing
as to the ability of the strand to meet any requirement of this
specification, two additional tests shall be made on a sample of
strand from the same reel or pack, and if failure occurs in either
of these tests, the strand shall be rejected.
13. Certification
13 If outside inspection is waived, a manufacturer&#;s cer-
tification that the material has been tested in accordance with
and meets the requirements of this specification shall be the
basis of acceptance of the material. The certification shall
include the specification number, year-date of issue, and
revision letter, if any.
13 The manufacturer shall, when requested in the order,
furnish a representative load-elongation curve for each size and
grade of strand shipped.
13 When the modulus of elasticity of a seven-wire strand
is provided, the cross-sectional area used to compute that
modulus also shall be provided. The area provided in the
certification shall be the area used to calculate the modulus of
elasticity.
14. Packaging and Marking
14 The strand shall be furnished on reels or in reelless
packs having a minimum core diameter of 610 mm [24 in.],
unless otherwise specified by the purchaser. Lengths on reels or
in reelless packs shall be as agreed upon at the time of
purchase. The strand shall be well protected against mechani-
cal injury in shipping as agreed upon at the time of purchase.
Each reel or reelless pack shall have two strong tags securely
fastened to it showing the length, size, type, grade, ASTM
designation A 416/A 416M, and the name or mark of the
manufacturer. One tag shall be positioned where it will not be
inadvertently lost during transit, such as the core of a reelless
pack. The other tag shall be placed on the outside for easy
identification.
14 For Government Procurement Only &#; When specified
in the contract or order, and for direct procurement by or direct
shipment to the U. government, material shall be preserved,
packaged, and packed in accordance with the requirements of
MIL-STD-163. The applicable levels shall be as specified in
the contract. Marking for shipment of such material shall be in
accordance with Fed. Std. No. 123 for civil agencies and
MIL-STD-129 for military agencies.
15. Keywords
15 prestressed concrete; seven-wire strand (tendon); steel
wire
SUPPLEMENTARY REQUIREMENTS
Supplementary requirements shall apply only to 15-mm (0-in.) strand, Grade 270 used in
prestressed ground anchors or similar applications and shall be specified at the time of order
placement. These requirements are not applicable to strand used in prestressed concrete applications.
S1. Bond Capacity
S1 The results of bond-capacity tests performed in accor-
dance with Specification A 981 shall be submitted to the
purchaser. The strand samples, on which tests were performed,
shall be from different lots and shall be representative for the
strand ordered.
S1 The average pull force from six pull tests, performed in
accordance with Specification A 981, required to reach the
0-mm (0-in.) displacement described therein shall be at
least 35 kN ( lbf), with the individual minimum test
value not less than 30 kN ( lbf). For any future retests,
without changes in the manufacturing method and materials
used, three tests shall be considered as adequate.
S1 Retests &#;If the test specimens fail to satisfy S1, six
additional tests shall be performed, and the results shall satisfy
the acceptance criteria. Strand that failed the retest shall not be
considered acceptable for the use in prestressed ground an-
chors.
S1 Annual Tests &#;The pull tests shall be performed annu-
ally as a minimum or repeated when, in the opinion of the
producer, a process change is made which is believed could
decrease the bond capacity of the strand.
The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection
with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such
patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and
if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards
and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your
views known to the ASTM Committee on Standards, at the address shown below.
This standard is copyrighted by ASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA -, United States.
Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at
610-832- (), 610-832- (fax), or service@astm (); or through the ASTM website (astm).
Comments
Please Join Us to post.
0